package wechat

import (
	"cls/internal/domain/payment"
	"cls/pkg/logger"
	"crypto/md5"
	"encoding/hex"
	"encoding/xml"
	"fmt"
	"sort"
	"strings"
)

// Config 微信支付配置
type Config struct {
	AppID     string // 公众号ID
	MchID     string // 商户号
	APIKey    string // API密钥
	NotifyURL string // 支付回调通知地址
}

// Service 微信支付服务
type Service struct {
	config Config
	client *APIClient
	log    logger.Logger
}

// NewService 创建微信支付服务
func NewService(config Config, log logger.New) *Service {
	return &Service{
		config: config,
		client: NewAPIClient(config),
		log:    log("cls:payment:wechat"),
	}
}

// CreatePayment 创建支付订单
func (s *Service) CreatePayment(order *payment.Payment) (map[string]interface{}, error) {
	// 构建统一下单请求
	req := &UnifiedOrderRequest{
		Body:       order.Description,
		OutTradeNo: order.OrderNo,
		TotalFee:   fmt.Sprintf("%d", order.Amount),
	}

	// 调用统一下单接口
	resp, err := s.client.UnifiedOrder(req)
	if err != nil {
		return nil, fmt.Errorf("创建支付订单失败: %v", err)
	}

	// 检查响应结果
	if resp.ReturnCode != "SUCCESS" {
		return nil, fmt.Errorf("微信支付接口返回错误: %s", resp.ReturnMsg)
	}

	if resp.ResultCode != "SUCCESS" {
		return nil, fmt.Errorf("微信支付业务处理失败: %s", resp.ErrCodeDes)
	}

	// 返回支付二维码链接
	return map[string]interface{}{
		"code_url": resp.CodeURL,
	}, nil
}

// VerifyNotify 验证支付回调通知
func (s *Service) VerifyNotify(notifyData string) (map[string]string, error) {
	// 解析XML数据
	var notify struct {
		ReturnCode    string `xml:"return_code"`
		ReturnMsg     string `xml:"return_msg"`
		ResultCode    string `xml:"result_code"`
		ErrCode       string `xml:"err_code"`
		ErrCodeDes    string `xml:"err_code_des"`
		OutTradeNo    string `xml:"out_trade_no"`
		TotalFee      string `xml:"total_fee"`
		TransactionID string `xml:"transaction_id"`
		Sign          string `xml:"sign"`
	}

	if err := xml.Unmarshal([]byte(notifyData), &notify); err != nil {
		return nil, fmt.Errorf("解析通知数据失败: %v", err)
	}

	// 验证签名
	if !s.client.verifySign(&notify) {
		return nil, fmt.Errorf("签名验证失败")
	}

	// 检查支付结果
	if notify.ReturnCode != "SUCCESS" || notify.ResultCode != "SUCCESS" {
		return nil, fmt.Errorf("支付失败: %s", notify.ErrCodeDes)
	}

	return map[string]string{
		"order_no":       notify.OutTradeNo,
		"amount":         notify.TotalFee,
		"transaction_id": notify.TransactionID,
	}, nil
}

// generateSign 生成签名
func (s *Service) generateSign(params map[string]string) string {
	// 按键排序
	var keys []string
	for k := range params {
		if k != "sign" && params[k] != "" {
			keys = append(keys, k)
		}
	}
	sort.Strings(keys)

	// 拼接字符串
	var builder strings.Builder
	for i, k := range keys {
		if i > 0 {
			builder.WriteString("&")
		}
		builder.WriteString(k)
		builder.WriteString("=")
		builder.WriteString(params[k])
	}
	builder.WriteString("&key=")
	builder.WriteString(s.config.APIKey)

	// MD5加密
	h := md5.New()
	h.Write([]byte(builder.String()))
	return strings.ToUpper(hex.EncodeToString(h.Sum(nil)))
}

// verifySign 验证签名
func (s *Service) verifySign(notifyData, sign string) bool {
	// TODO: 实现签名验证逻辑
	return true
}